Thwocker was one of the long lost Activision prototypes that finally surfaced in 2001 when it was found a thrift shop along with some other prototypes. Like most other unreleased Activision games, Thwocker was never mentioned in any catalogs or announced at any gaming expos. Apparently Activision liked to keep their games secret until they were sure it was going to be released. Not a bad policy.
Thwocker is a game as strange as its name. Written by Charlie Heath (of Reactor fame), Thwocker was described as "Joust with musical instruments". While this isn't a bad description, it really doesn't illustrate all the gameplay elements that make Thwocker such an interesting game. You control a little conductor (who happens to look like a bowling ball) who must bounce around a maze collecting musical notes for his song. Along the way you must avoid various musical instruments that are out to get you (can't we all just get along?). However you can't go grabbing just any musical notes, you must collect them in the proper order. The current note type needed is shown at the bottom of the screen. If you touch the wrong type of note you will ricochet off it, send your conductor flying across the screen (usually into a waiting enemy). After collecting all the notes you must grab the treble clef symbol at the top of the maze to start the song. Once the song starts to play your character will be able to touch enemies and notes for points (think of it as a power pellet) until the song ends. After completing the song you can exit the level by touching the exit square.
The controls in Thwocker take a little getting used to, but they're not as tricky as they first seem. The levels seem to be made out of some kind of springy material, so your character bounces all around the screen. You can control how high you bounce by pushing up and down. Pushing down will make the conductor take little bounces, while pressing up (as you touch the ground) will make him bounce really high. You can stop bouncing all together by pressing the fire button, which will make the conductor sort of "skip" across the level. You will need to master all these bouncing techniques to successfully complete the level.
Sadly Thwocker is incomplete as there is no way to exit the level. It was thought that they player simply needed to touch the exit square after completing the song to finish the level, but this does not appear to be the case. It appears that the code that allows you to destroy the enemy after completing the song also allows you to destroy the exit, so the game appears to be unwinnable. However after careful examination of the game code, it appears there may be more to Thwocker than meets the eye. Apparently the player must somehow "combine" the two voices of the song after it starts playing to exit the level. Unfortunately we haven't figured out how this portion of the game works yet, but it may have something to do with picking up certain objects on the screen. However just because the code to exit the level exists doesn't mean it's actually possible to do it in the game, so Thwocker may still be unwinnable after all.
Thankfully you can still see the other levels by selecting the higher difficulty levels at the title screen. Programmer Charlie Heath (who owns the only other known prototype) has said that Thwocker is only around 80% complete when development was cancelled. One has to wonder what else Charlie had in store for us, as other than the lack of the ability to finish a level Thwocker seems fully playable and complete. Perhaps there were some minor game or difficulty issues left to work out? The only glitch I've seen in the game is on the game select screen. The game number should go from 1 to 10, but there are six games in between 9 and 10. These game numbers are represented by a space, another space, a white eigth note, a space, a white quarter note, and a dot. This is most likely because the game numbers are stored in hex (base 16), so there are 16 games represented. It is unknown if Charlie actually intended for there to be 16 games or only 10, but since they all seem to be playable one comes to the conclusion that they were indeed planned.
Thwocker, along with Kabobber, were victims of the collapsing videogame market in 1984. It was around this time that Activision decided it was time to get out of the 2600 market and concentrate on the new gaming fad Home Computers. Activision did release a few new games during the 2600 revival years, but Thwocker was not one of them. At this point Activision was concentrating on converting arcade games to the 2600 instead of releasing older unpublished games. What they didn't realize is that the older games they were ignoring were much better than the new games they were putting out (but that's another story). Thankfully Thwocker finally got its long overdue release, and now we can all enjoy what has to be one of the most unique 2600 games I've ever seen.